Compare the tensile strength of dry and wet cotton yarns by lea method and calculate their CLSP.
The strength along the length of a body is known as its tensile strength also called linear strength of that body. In the textile fibers or yarns only tensile strength is calculated due to high length to width ratio of the textile materials. The tensile strength values of the dry and wet cotton yarns varies very much from each other. The strength of wet cotton yarns is greater than that of dry cotton yarns. This is due to the formation of hydrogen bonds between the water molecules and the hydroxyl groups in the cellulosic rings of the cotton fibers in the wet state. There is one phenomenon known to stand that when the cotton gets wet its crystalline region increases hence the strength of the fibrous structure increases.
Figure 1: Lea Tensile Strength Tester
The most important properties of a textile product is its mechanical properties. And these properties are a combination of the inherent mechanical properties of the fibers itself and along the manufacturing of a textile product many process increases or decreases these properties. So it is important to consider mechanical properties of the textile materials at every step of the manufacturing process.
Tensile strength is most widely studied mechanical property due to the shape of a textile product. Undergoing through different forces and loads the textile material deforms hence tensile strength of a textile product has a great importance.
So here in this experiment we will find out how to calculate the tensile strength of a cotton yarn using lea method. We will also find out the CLSP values of the dry cotton yarns. CLSP stands for Count Lea Strength Product. It is calculated by multiplying English Count of yarn into its Tensile Strength. It is basically a tool for determining the strength of a yarn. CLSP values in the range of 1800-2200 for cotton are considered good. Lower than 1800 values are considered that the strength of cotton is bad. The experiment is as below:
- To calculate the tensile strength of cotton yarns in both dry and wet state.
- To calculate CLSP of dry cotton yarns.
- To compare the tensile strength of dry and wet cotton yarns.
- Dry cotton yarn.
- Wrapping Reel
- Tensile Strength Testing Machine
- Weighing Balance
Temperature of Dry Yarns = 29 C
Temperature of Wet Yarns = 26 C
Difference in temperature of Dry and Wet Yarns = 3 C
Humidity of the Lab = 70 RH
- Dry cotton yarn was taken.
- 8 leas of 120 yards of that yarn were made using the wrapping reel.
- 4 of them were soaked in the water placed in the beaker.
- Weight of each of the dry samples were taken on the weighing balance.
- These were now placed on the tensile strength testing machine.
- Tensile strength of both dry and wet yarns were calculated.
Length of lea taken = 120 yards
120 yards = 10920 cm
English count = 0.0059 x (length of cm / weight in grams )
CLSP = Count Lea Strength Product = Count x Tensile Strength
Average Tensile Strength of Dry Cotton Yarns = 83.05 lbs
Average Tensile Strength of Wet Cotton Yarns = 113.85 lbs
% difference in Strength of dry and wet cotton yarns = 27%
Normal range = 10-15 % (According to ASTM standards)
CLSP values of Dry cotton yarns = 1676.81
To Compare the tensile strength of 100 % pure cotton and its blends, also calculating their CLSP values.
This experiment is done to see how same count of different types of yarns has different strength and CLSP. We will also see the factors on which tensile strength of a product depends upon and when to use which yarns for different applications.
Comparing the single yarn strength having different TPI and same count
This experiment was conducted to see how does twists per unit inch or TPI in a yarn effect its strength. For this purpose, other parameters like fiber type and count of yarn are kept constant.
Why do fabrics shrink? Shrinkage in Fabrics!
During the manufacturing process of fabric or we call it fabric processing, fabric comes in lot of tension and stretches when it moves from one machine to another which causes stretching in fabric structure and when this tension is removed, and fabric is relaxed it tends to get back in its original structure causing shrinkage.
Worsted Yarn Manufacturing Process
A fine smooth yarn spun from combed long staple wool. Worsted yarns are more tightly twisted than the bulkier woolen yarns. The soft, heavy yarn is strong and durable and is often used for sweaters. Worsted yarns are also used for fine dress fabrics and suit materials.